> I might build it myself

Build it if you think it'd be fun or something worthwhile for your CV. Don't build it because you want it to be a useful, nudity-free chat service. People have tried that (including Chat Roulette itself).

It's hard to get people to use things with their real identities. Unfortunately, anonymity also enables trolling. I think it's impossible to have a random chat site without masturbation. It is, bizarrely, part of human nature to troll.

Honing your social skills can be hard, but you might want to try clubs or meetups in your city. Video chat isn't much like real-life socializing anyway.